1. Field of the Invention
present invention relates generally to seismic data acquisition apparatus and methods and more particularly to a permanently deployed multicomponent seafloor seismic data acquisition system.
2. Description of the Related Art
the oil and gas industry wells are often drilled into underground formations at offshore locations. Once a well is successfully drilled, oil, gas, and other formation fluids can be produced from the formation. It is desirable during production to monitor formation parameters on a relatively continuous basis in order to effectively manage the field. Monitoring is performed using an array of seismic sensors located on the seafloor. Monitoring might be passive or active. In passive monitoring sensors detect seismic events without having the system induce the seismic event by introducing acoustic energy into the earth. Active monitoring as achieved when an acoustic energy source, e.g., an air gun, explosives, etc. is used to induce the seismic event.
The acoustic energy is detected by the sensor array and the array output is recorded at a central recorder for later processing and/or assessments of the field parameters.
Typical seafloor monitoring systems suffer from several disadvantages. The typical system is not expandable, thus the typical system is usually deployed at the system level and then tested for proper operation. Any failure is detected only at the system level thereby making troubleshooting and repair difficult and costly.
Another disadvantage in a non-expandable system is that changes in system layout and size are usually impossible without redesigning the entire system. Moreover, an existing system would require costly rework in order to expand the system.
Another disadvantage in the typical seismic monitoring system is high deployment costs. The cables associated with the typical system are large and expensive to deploy.